During embryonic development, different cell types acquire specific patterns of gene expression by interpreting chemical signals as a function of their location within the embryo. In this talk, I will discuss two fundamental questions in developmental patterning. First, how does pattern formation depend on temporal changes in signaling? And second, how do gene expression patterns respond to natural variations in embryo size within a population? In the first part of the talk, I will present a modeling-based approach aimed to compare the effects of transient vs. steady state signaling on embryonic patterning and illustrate how it can be used as a tool to design genetic experiments in practical cases. Then, I will show recent high-throughput data to investigate the relationship between the location of patterns of gene expression and egg size in populations of fruit fly embryos. Our data reveal that several genes display a remarkable ability to scale patterns to size and suggest the existence of developmental mechanisms that ensure the correct specification of positional information relative to the size of the embryo.